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Biomedical subjects

S P Chee

Publications and source records attributed to S P Chee.

At least 19 recordsLinked to original sources
PubMed2006

Multifocal venous malformations: two interesting case presentations.

INTRODUCTION: Multiple venous abnormalities involving the orbit, head and neck regions have been previously described. We present two similar cases of low-flow orbital venous vascular malformations (VVMs) in association with multiple low-flow VVMs in the head and neck as well as in the peripheral limb. Literature search revealed that this association has not been previously reported. METHODS: Retrospective review of two patients with multifocal VVMs was performed. RESULTS: Case 1: A 46 year-old Chinese female had a history of multiple vascular lesions involving the right orbit, the tongue, right neck region, right arm and one finger. Valsalva manoeuvre resulted in distension of these lesions. CT scan of the orbits demonstrated bilateral low-flow VVMs. CT angiogram also revealed multiple developmental venous anomalies in the brain. Case 2: A 16 year-old Chinese female had a history of multiple venous malformations involving the neck, left forearm and oral region. Dynamic manoeuvres demonstrated the distensible nature of these lesions. MRI scans of the orbits showed bilateral extraconal low-flow VVMs. Similar mass lesions were seen on MRI scans of the neck. CONCLUSIONS: Multiple cervicofacial venous malformations with developmental abnormalities of the intracranial venous system have been described previously. However, their associations with similar VVMs in the peripheral limb regions have not been reported. Our cases illustrate this rare association. VVMs appear to be benign in nature with symptoms mainly due to mass effect. Management can be conservative in the absence of any sight threatening complication.

Adolescent↗
PubMed2006

Pseudoretinoblastoma in enucleated eyes of Asian patients.

INTRODUCTION: Retinoblastomas of the eye are a cause of childhood blindness and have a high rate of mortality, as well as a hereditary mode of transmission. Other conditions that mimic retinoblastomas are known as pseudoretinoblastomas, and are managed differently. Although pseudoretinoblastoma and the accuracy of retinoblastoma diagnosis have been reviewed in Caucasian patients, published studies in Asian patients are lacking. The purpose of this article is to report our experience with pseudoretinoblastomas in two major ophthalmological centres in Asia. METHODS: A case series of 28 enucleations carried out for suspected retinoblastoma at the Singapore National Eye Centre and KK Women's and Children's Hospital, Singapore, between January 1991 and December 2002, is reported. All cases were subjected to a detailed history from parents, followed by external ocular examination, slit-lamp biomicroscopy and binocular indirect ophthalmoscopy. Ancillary studies, such as B-scan ultrasonography and computed tomography, were employed as necessary to confirm the diagnosis. Histology was obtained on all cases. RESULTS: Of the 28 cases, 25 (89 percent) were found on histological analysis to be retinoblastomas. Three (11 percent) were pseudoretinoblastomas. There were two cases of Coat's disease and a case of presumed ocular toxocariasis. These three cases were described in detail. CONCLUSION: Although our sample size is small, the percentage of confirmed retinoblastomas was found to be only slightly higher than that found in western countries. Our findings are consistent with their findings that Coat's disease and presumed ocular toxocariasis are the more common causes of pseudoretinoblastoma.

Asian People↗
PubMed2004

Integrated hydroxyapatite implant and non-integrated implants in enucleated Asian patients.

INTRODUCTION: This study compares the outcome and complications of integrated hydroxyapatite implant and non-integrated orbital implants following enucleation in Asian patients. MATERIALS AND METHODS: This is a retrospective study of enucleated patients with coralline hydroxyapatite implants versus non-integrated implants (acrylic, glass and silicone) at the Singapore National Eye Centre from January 1991 to December 2000. The outcomes measured were implant migration, extrusion, socket infection, conjunctival dehiscence and implant exposure. Statistical analysis was done using the 2-sample t-test. RESULTS: Twenty-one patients had the hydroxyapatite implant and 38 non-integrated implants (27 acrylic, 9 glass and 2 silicone). The mean duration of follow-up was 2.7 years and 4 years for the hydroxyapatite implant and non-integrated implants respectively. Three patients with pre-existing severe socket contracture before enucleation surgeries were excluded from the study. Four cases of implant migration, 4 cases of implant extrusion and 3 cases of socket infection were encountered; all were sockets fitted with non-integrated implants. There was a higher rate of conjunctival dehiscence for sockets with hydroxyapatite implants (6 out of 21) compared to sockets with non-integrated implants (3 out of 35). This was statistically significant (P = 0.048). CONCLUSIONS: Implant complications of migration, extrusion and socket infection were found in non-integrated implants and none in coralline hydroxyapatite implants, which had a significantly higher rate of conjunctival dehiscence. Most of these were easily managed with only a small number progressing to implant exposure.

Adult↗
PubMed2001

Is Posner Schlossman syndrome benign?

PURPOSE: To determine the clinical course of patients with Posner Schlossman syndrome (PSS). DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Fifty-three eyes of 50 patients. METHODS: The case notes of all patients with PSS seen at the Uveitis Clinic of Singapore National Eye Centre were reviewed for evidence of glaucoma damage and risk factors. MAIN OUTCOME MEASURES: Visual field and optic disc changes consistent with glaucoma. RESULTS: There were 28 men and 22 women, and their mean age at onset was 35 years. Fourteen eyes (26.4%) were diagnosed to have developed glaucoma as a result of repeated attacks of PSS. Patients with 10 years or more of PSS have a 2.8 times higher risk (95% confidence interval 1.19-6.52) of developing glaucoma compared with patients with less than 10 years duration of the disease. Nine eyes (17%) underwent glaucoma filtering surgery with antimetabolites. Their postoperative follow-up ranged from 15 to 50 months (mean, 37 months). Four eyes continued to have episodes of iritis after surgery, and one of these eyes had elevated intraocular pressure during the event. CONCLUSIONS: A significant number of patients with PSS have glaucoma develop over time, and they need to have their optic disc appearance and visual fields carefully monitored.

Adolescent↗
PubMed2001

Amniotic membrane transplantation in entropion surgery.

PURPOSE: To evaluate the role of amniotic membrane transplantation in the management of cicatricial eyelid entropion. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: Eighteen consecutive patients with cicatricial entropion. METHODS: A gray line lid split procedure with vertical anterior lamella repositioning was performed on 25 eyelids (upper or lower) of 18 patients with moderate to severe cicatricial entropion. Preserved human amniotic membrane (AM) was used to cover the bare tarsus up to the lid margin and secured with running 7-0 Vicryl. Impression cytology of the AM was performed at various stages postoperatively to study the epithelialization process. MAIN OUTCOME MEASURES: (1) Reepithelialization of bare tarsus, (2) extent of tarsal shrinkage, (3) recurrence of entropion. RESULTS: All the AM grafts took well. The most common complication was hemorrhage below the graft, which occurred in six cases. Complete success with no lashes touching the globe was achieved in 22 of 25 (88%) lids after a minimum follow-up of 12.0 months. The mean follow-up was 17.8 months. Two cases (qualified success) had recurrent trichiasis treated successfully with electrolysis. One case with severe trachomatous upper lid entropion recurred 14 months after surgery. The AM accelerated the epithelialization of bare tarsus; this was demonstrated by lack of fluorescein staining and reversion to skin color within 2 to 3 weeks. However, AM could not prevent tarsal shrinkage. Impression cytology demonstrated that features of conjunctival epithelium were present for the first postoperative month, but this was gradually replaced by squamous metaplasia, with keratinization appearing as early as 3 weeks postoperatively. CONCLUSIONS: The use of AM in a lid split procedure for correction of cicatricial entropion helps the bare tarsus epithelialize rapidly and improves the initial cosmetic result of surgery.

Adult↗
PubMed2001

Randomized clinical trial of Surodex steroid drug delivery system for cataract surgery: anterior versus posterior placement of two Surodex in the eye.

OBJECTIVE: To evaluate safety and antiinflammatory efficacy of placing two Surodex (Oculex Pharmaceuticals, Inc., Sunnyvale, CA) in the eye after cataract surgery in comparison with steroid eyedrops and to compare anterior versus posterior chamber placement. DESIGN: Randomized, masked, controlled trial. PARTICIPANTS: One hundred four eyes of 104 Asian patients undergoing extracapsular cataract extraction with intraocular lens implantation were examined. Of these, 33 eyes of 33 patients served as control eyes (group A). INTERVENTION: Two Surodex pellets were inserted in the anterior chamber (AC) of 35 eyes (group B), and two Surodex pellets were inserted in the ciliary sulcus of 36 eyes (group C) at the conclusion of surgery. Control eyes received neither Surodex nor a placebo implant, but were prescribed conventional 0.1% dexamethasone eyedrops four times daily for 4 weeks. MAIN OUTCOME MEASURES: Anterior chamber flare and cells were graded clinically at the slit lamp. Anterior chamber flare was assessed objectively with the Kowa FC500 Laser Flare Meter (Kowa Co. Ltd, Tokyo, Japan). Intraocular pressure and corneal endothelial specular microscopy with morphometric cell analysis were performed for up to 1 year after surgery. RESULTS: Lower flare meter readings occurred in both Surodex groups at all postoperative visits, as compared with the dexamethasone eyedrop group, with statistical significance at days 4 (P = 0.001), 8 (P = 0.001), and 15 (P = 0.02). No difference in flare occurred between AC and ciliary sulcus placement. Clinical slit-lamp assessment of anterior chamber flare and cells showed no difference between Surodex-treated eyes and dexamethasone-treated eyes. Nine of 33 eyes (27.3%) in group A required steroid augmentation, as opposed to 4 of 71 eyes (5.6%) in groups B and C. Inflammatory symptoms were reduced in the Surodex-treated eyes, with statistical significance for ocular discomfort (P = 0.001), photophobia (P = 0.04), and lacrimation (P = 0.01). No complications occurred with Surodex-treated eyes, and no significant difference in endothelial cell loss was noted between Surodex-treated eyes and dexamethasone-treated eyes up to 1 year after surgery. CONCLUSIONS: Intraocular placement of two Surodex is a safe and effective treatment method to reduce intraocular inflammation after cataract surgery and clearly is superior to eyedrops in reducing inflammatory symptoms and aqueous flare as measured with the laser flare meter. No difference in efficacy between AC placement and ciliary sulcus placement of Surodex was detected in this study.

Aged↗
PubMed2001

Endogenous endophthalmitis.

Endogenous endophthalmitis still presents a diagnostic and therapeutic challenge even with improvements in therapeutic modalities. The main prognostic factor is the virulence of the causative organism: once the organism enters the eye, it rapidly destroys ocular tissues. With the increasing ability to prolong the life of very ill patients, incidence of endogenous endophthalmitis is expected to increase. Ophthalmologists must be ever more vigilant, because prompt treatment offers the best chance of saving the eye.

Endophthalmitis↗
PubMed2001

Nodular anterior scleritis associated with ocular trauma.

It is accepted that ocular trauma may be the precipitant of non-infectious uveitis. We report the case of a patient who developed unilateral nodular anterior scleritis following ocular trauma. Infection and systemic inflammatory diseases were excluded as causes of the inflammation. Our observations suggest the possibility that ocular trauma may act as a trigger for scleritis.

Adult↗
PubMed2001

Patient reliability in the administration of topical ocular medication.

PURPOSE: To evaluate patient's reliability in the administration of eyedrops. METHOD: The study is based on a randomised, controlled clinical trial in which a steroid-containing drug delivery system (DDS) was directly compared to conventional steroid eyedrops after cataract surgery. 32 eyes undergoing extracapsular cataract extraction with intra-ocular lens insertion received a DDS, while 31 eyes received 0.1% dexamethasone eyedrops q.d.s for 30 days. Patients with DDS were given a placebo eyedrop in the form of 0.9% sodium chloride, while all 63 eyes received topical chloramphenicol eyedrops q.d.s for 30 days. At the conclusion of the 30 day visit, the eyedrop containers were collected and the residual volume of medication remaining in each bottle was then measured to the nearest 10 microlitre using a pipette. RESULTS: 31 patients returned the complete set of eyedrop containers. There was no statistical significant difference in the volume used between the types of eyedrops, sex and diabetic status. All the patients used more than the prescribed amount. Older patients tended to use less medication. CONCLUSION: The amount of medication that patients actually administered in this trial varied widely according to the individual, and patient age may be a factor affecting compliance in using eyedrops.

Age Factors↗
PubMed2000

Endogenous bacterial endophthalmitis: an east Asian experience and a reappraisal of a severe ocular affliction.

PURPOSE: To report 32 eyes of 27 patients with endogenous bacterial endophthalmitis seen over a 4 year period. Features and outcomes of this condition in the current series and the cases reported in the literature from 1986-1998 were reviewed. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: All patients with this condition seen at the three participating general hospitals were included. INTERVENTION: A review of the systemic and ocular characteristics, therapeutic methods, and final outcomes in patients afflicted with this condition. MAIN OUTCOME MEASURES: Features studied included patients' demographic characteristics, microbiology, source of infection, ocular features, therapeutic interventions, final visual and anatomic outcomes. RESULTS: Nineteen (70%) of the 27 incriminating organisms in this case series were gram negative microbes, with Klebsiella pneumoniae infections alone being responsible in 16 (60%) cases. Hepatobiliary tract infection was the source of bacteremia in 13 (48%) patients. Only nine (28%) eyes obtained good final visual acuity (20/120 or better), and two eyes were enucleated/eviscerated. A literature review of 209 patients with endogenous endophthalmitis over a 12 year period showed a similar increase in the frequency of gram negative microbes as the responsible organism, especially among the East Asian population. Overall, 22% had bilateral involvement; two thirds of patients had predisposing factor(s) or underlying illness(es), and diabetes mellitus was present in 46%. Thirty-four percent of all eyes obtained counting finger or better final vision, and 16% had their eyes eviscerated or enucleated. Infections with virulent organisms (gram negative rods, Serratia, Bacillus) usually denoted a grave visual prognosis; however, a media that was not opaque on presentation was usually associated with a good prognosis. CONCLUSION: Metastatic ocular infection is not uncommon despite the availability of modern antibiotic therapy. Among the East Asian population, the patient at highest risk is a diabetic patient with Klebsiella pneumoniae hepatobiliary infection. In contrast, in the Caucasian population, this condition occurs in predisposed patients with gram-positive bacteremia arising from endocarditis or skin/joint infections. The final visual outcome in patients with endogenous bacterial endophthalmitis in the recent 12 years has not differed significantly from five decades ago.

Adult↗
PubMed2000

Capsular block syndrome: A case series.

Capsular block syndrome (CBS) or capsular bag distension syndrome has been described after cataract removal with in-the-bag placement of a posterior chamber intraocular lens in the presence of an anterior continuous curvilinear capsulorhexis. Features of CBS include shallowing of the anterior chamber and an unexpected myopic overrefraction; occasionally, there is a persistent uveitis. The patient may be mistakenly diagnosed with pupil block glaucoma or endophthalmitis. We report 9 cases of CBS and their initial diagnoses and management. In 1 case, the capsular bag distention and anterior chamber shallowing are illustrated by ultrasound biomicroscopy.

Adult↗
PubMed2000

Graves' ophthalmopathy in the absence of elevated free thyroxine and triiodothyronine levels: prevalence, natural history, and thyrotropin receptor antibody levels.

The aims of this study were to (a) determine the prevalence of patients without elevated thyroid hormone levels in Graves' ophthalmopathy (GO) using current generation free thyroid hormone assays, (b) measure the prevalence of thyrotropin receptor antibodies (TRAb) in these cases, and (c) identify possible predictors of hyperthyroidism. Over a 30-month period, 1020 cases of thyroid eye disease were evaluated, of which only 19 (1.9%) met the diagnostic criteria. Ten (1%) had subclinical thyrotoxicosis, 7 (0.7%) were euthyroid, and 2 (0.2%) were hypothyroid as determined by a third-generation thyrotropin (TSH) assay. TRAb levels were measured in 16 of these 19 patients. The prevalence of TRAb varied according to the assay used. Polyethylene glycol-extracted thyroid-stimulating immunoglobulin (PEG-TSI), unfractionated thyroid-stimulating immunoglobulin (uTSI), first-generation porcine TSH-binding inhibitory immunoglobulin (pTBII), and second-generation human TSH-binding inhibitory immunoglobulin (hTBII) assays were positive in 93.8%, 50%, 18.8%, and 81.3% of patients, respectively. TRAb was detected by at least one method in all patients. Patients were followed up for 15 to 45 months. Hyperthyroidism developed in 4 patients (25%). Suppressed TSH levels and elevated TBII were predictors of hyperthyroidism. When sensitive assays are used, the prevalence of GO patients without elevated thyroid hormone levels is extremely low. The sensitivities of assays for TRAb detection differ substantially in these cases. PEG extraction improves the detection rate of TSI (p = 0.02), and hTBII assays improve the detection of TBII in these patients (p = 0.002). The high prevalence of TRAb in such cases supports a role for these antibodies in the pathogenesis of thyroid-associated eye disease.

Adolescent↗
PubMed2000

Analysis of variation in success rates in conjunctival autografting for primary and recurrent pterygium.

AIMS: To evaluate the success rates of conjunctival autografting for primary and recurrent pterygium performed in a tertiary ophthalmic centre. METHODS: The outcome of 139 cases with primary pterygia and 64 cases with recurrent pterygia who underwent excision with conjunctival autografting was retrospectively reviewed. Outcome was evaluated in terms of recurrence of pterygia onto the cornea. The recurrence rates were determined using Weibull survival functions, in a mixture model that included a component allowing for cure. The suitability of this model was verified using Turnbull's non-parametric method for interval censored data (1974). Estimated recurrence free probabilities were based on the fitted Weibull survival curves. RESULTS: Mean follow up was 8.4 months in the primary group, and 9.5 months for the recurrent group. 29 out of 139 cases of primary pterygia recurred (20.8%) while 20 out of 64 cases in the recurrent group (31.2%) recurred. Recurrence rates varied widely among surgeons, ranging from 5% to 82%. Recurrence rates were inversely related to previous experience in performing conjunctival grafting. The recurrence free probability was 84% at 3 months, 73% at 1 year for primary pterygia, and 80% at 3 months, 67% at 1 year for recurrent pterygia. There was no statistical difference in recurrence rates between primary and recurrent groups (p= 0.80). CONCLUSION: The success of conjunctival autografting for pterygium in this series varies widely, and may be related to a significant learning curve or differing surgical techniques for this procedure. This may account for the wide variation in reported success of this procedure in the ophthalmic literature.

Adult↗
PubMed2000

Necrotising scleritis after bare sclera excision of pterygium.

AIM: To report cases of scleral necrosis after simple pterygium excision in which adjunctive treatment was not used. METHODS: We reviewed four patients who presented with scleral melt after pterygium excision without the use of adjunctive treatment in the form of beta irradiation, mitomycin C, or thiotepa. Each patient was thoroughly investigated to exclude underlying disease. RESULTS: Certain similarities were found between our patients with pterygium melt and cases of surgically induced necrotising scleritis including the location of melt, associated inflammation, and its response to steroid treatment in the latent period before they presented. CONCLUSION: Bare sclera pterygium excision can cause surgically induced necrotising scleritis years after the surgery.

Aged↗
PubMed2000

Branch retinal artery occlusion secondary to a Hollenhorst plaque.

Retinal arterial circulation obstruction has serious implications. It may result in acute visual loss, but more significantly, it implies that the patient's systemic health needs further review and investigations in order to prevent severe and life-threatening consequences such as myocardial infarction and cerebrovascular accidents. We report a case of a patient with branch retinal artery occlusion with the presence of a Hollenhorst plaque.

Aspirin↗
PubMed2000

Acute retinal necrosis syndrome complicating chickenpox.

Chickenpox may be complicated by ocular involvement. In these patents, acute retinal necrosis usually forms a relatively mild course. Systemic antiviral treatment during the acute phase of the disease is recommended. Rarely, retinal detachment may develop, resulting in blindness. It is strongly recommended that patients with chickenpox who develop visual symptoms should be referred for an ophthalmological opinion early.

Acyclovir↗